 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.activities;

 import java.util.Set ;

 /**
  * An instance of this interface allows clients to manage activities, as
  * defined by the extension point <code>org.eclipse.ui.activities</code>.
  * <p>
  * This interface is not intended to be extended or implemented by clients.
  * </p>
  *
  * @since 3.0
  */
 public interface IActivityManager {

     /**
      * Registers an instance of <code>IActivityManagerListener</code> to
      * listen for changes to properties of this instance.
      *
      * @param activityManagerListener
      * the instance to register. Must not be <code>null</code>.
      * If an attempt is made to register an instance which is
      * already registered with this instance, no operation is
      * performed.
      */
     void addActivityManagerListener(
             IActivityManagerListener activityManagerListener);

     /**
      * Returns an instance of <code>IActivity</code> given an identifier.
      *
      * @param activityId
      * an identifier. Must not be <code>null</code>
      * @return an instance of <code>IActivity</code>.
      */
     IActivity getActivity(String activityId);

     /**
      * Returns an instance of <code>ICategory</code> given an identifier.
      *
      * @param categoryId
      * an identifier. Must not be <code>null</code>
      * @return an instance of <code>ICategory</code>.
      */
     ICategory getCategory(String categoryId);

     /**
      * Returns the set of identifiers to defined activities.
      * <p>
      * Notification is sent to all registered listeners if this property
      * changes.
      * </p>
      *
      * @return the set of identifiers to defined activities. This set may be
      * empty, but is guaranteed not to be <code>null</code>. If this
      * set is not empty, it is guaranteed to only contain instances of
      * <code>String</code>.
      */
     Set getDefinedActivityIds();

     /**
      * Returns the set of identifiers to defined categories.
      * <p>
      * Notification is sent to all registered listeners if this property
      * changes.
      * </p>
      *
      * @return the set of identifiers to defined categories. This set may be
      * empty, but is guaranteed not to be <code>null</code>. If this
      * set is not empty, it is guaranteed to only contain instances of
      * <code>String</code>.
      */
     Set getDefinedCategoryIds();

     /**
      * Returns the set of identifiers to enabled activities.
      * <p>
      * Notification is sent to all registered listeners if this property
      * changes.
      * </p>
      *
      * @return the set of identifiers to enabled activities. This set may be
      * empty, but is guaranteed not to be <code>null</code>. If this
      * set is not empty, it is guaranteed to only contain instances of
      * <code>String</code>.
      */
     Set getEnabledActivityIds();

     /**
      * Returns an instance of <code>IIdentifier</code> given an identifier.
      *
      * @param identifierId
      * an identifier. Must not be <code>null</code>
      * @return an instance of <code>IIdentifier</code>.
      */
     IIdentifier getIdentifier(String identifierId);

     /**
      * Removes an instance of <code>IActivityManagerListener</code>
      * listening for changes to properties of this instance.
      *
      * @param activityManagerListener
      * the instance to remove. Must not be <code>null</code>.
      * If an attempt is made to remove an instance which is not
      * already registered with this instance, no operation is
      * performed.
      */
     void removeActivityManagerListener(
             IActivityManagerListener activityManagerListener);
 }

